To measure the high voltage transmitted from an ignition coil to the spark plug via a cable for the purpose of testing the functioning of single-spark ignition coils, a tong-test instrument is already known, which can be clamped onto the outer shell of the line carrying the high voltage. For this purpose, two conductor surfaces of the tong-test instrument surround the high-voltage cable. In this manner, the ignition coil can be tested in the installed state. Ignition devices having multiple rod-type ignition coils for an internal combustion engine are known from German Published Patent Application No. 298 18 882. In this instance, the rod-type ignition coils are located within a so-called spark plug dome of the cylinder head of the internal combustion engine.
A high-voltage connector attached to the respective rod-type ignition coil, which establishes the connection between a high-voltage output of the rod-type ignition coil and a terminal stud of the spark plug that is mounted in a stationary manner in the spark plug dome, is inserted into the spark plug dome.
In internal combustion engines having rod-type ignition coils, in which the latter are directly connected to the spark plugs without the interconnection of a cable, an ignition coil test cannot be performed in the installed state of the rod-type ignition coils by using the known tong-test instrument since the secondary winding and the secondary circuit of the rod-type ignition coils for the ignition voltage diagnosis are partly inaccessibly located inside the spark plug domes.
For this reason, rod-type ignition coils today are tested in the uninstalled state. Requiring numerous auxiliary devices, the loose measuring structures used for this purpose, however, for safety-related reasons do not allow for the measurement to be carried out directly on the internal combustion engine. Moreover, the testing conditions of an uninstalled rod-type ignition coil are different that those of one that is installed. Consequently, the testing results do not completely match the actual values in the operating state or it is not possible to perform all tests under actual conditions.
The objective of the present invention is to provide an ignition coil tester in connection with a diagnostic tester for the component testing of a rod-type ignition coil uninstalled from an internal combustion engine.